Steering devices for oht

ABSTRACT

A steering device for an OHT according to some example embodiments of the present inventive concepts includes: an LM block; a steering plate fixedly installed to the LM block and provided with an insertion groove; a link installed in the insertion groove of the steering plate and tilted; a main bearing having an outer circumferential surface in contact with the link to reduce friction when the link is tilted; and a guide roller rotatably installed on a protrusion protruding from the link.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority, under 35 U.S.C. § 119, toKorean Patent Application No. 10-2021-0030035 on Mar. 8, 2021 in theKorean Intellectual Property Office, the disclosure of which isincorporated by reference herein in its entirety.

BACKGROUND

The present inventive concepts relate to steering devices for anoverhead hoist transport (OHT).

An overhead hoist transport (OHT) is a transportation containertransportation device for transporting transportation containers betweenfacilities within a semiconductor line, that is transport products(FOSB, MAC, CST, or the like). However, when the OHT enters a guiderail, a rotational radius of the guide rail is different from arotational radius of the guide roller provided in the steering devicefor an OHT, so uneven contact between the guide rail and the guideroller occurs. Accordingly, this may result in concentration of a loadon the guide roller.

SUMMARY

Some example embodiments of the inventive concepts provide a steeringdevice for an overhead hoist transport (OHT) configured to reduce orprevent damage to a guide rail and the steering device for an OHT, forexample based on being configured to reduce or prevent the likelihood ofimpacts between the OHT steering device and the guide rail. A steeringdevice according to any of some example embodiments may enable improved(e.g., increased) production in a semiconductor line due to reducing orpreventing damage to the guide rail and/or the steering device. Asteering device for an OHT according to any of some example embodimentsmay reduce or prevent the likelihood of a human accident based onreducing or preventing the likelihood of the OHT falling due to damageto the guide rail and the steering device for the OHT.

In addition, some example embodiments of the inventive concepts providea steering device for an OHT that can reduce mechanical vibrations andimpacts transmitted to a wafer while the OHT is running.

According to some example embodiments of the inventive concepts, asteering device for an OHT may include a linear motion (LM) block, asteering plate fixedly installed to the LM block and including one ormore inner surfaces at least partially defining an insertion groove inthe steering plate, a link tiltably installed in the insertion groove ofthe steering plate, a main bearing having an outer circumferentialsurface in contact with the link, the main bearing configured to reducefriction when the link is tilted in relation to the steering plate, anda guide roller rotatably installed on a protrusion protruding from thelink.

According to some example embodiments of the inventive concepts, asteering device for an OHT may include a linear motion (LM) block, asteering plate fixedly installed on an upper surface of the LM block andincluding one or more inner surfaces at least partially defining aninsertion groove in an upper surface of the steering plate, a link thatis at least partially within the insertion groove and is configured tobe tilted in response to an external force being applied to the link, amain bearing between the steering plate and the link, a guide rollerrotatably installed on an installation protrusion protruding from thelink, a cover configured to cover the main bearing and the insertiongroove of the steering plate, and a fixing member extending through thesteering plate, the fixing member configured to fix the main bearing inplace.

According to some example embodiments of the inventive concepts, asteering device for an OHT may include a linear motion (LM) block, asteering plate fixedly installed to the LM block and including one ormore inner surfaces at least partially defining an insertion groove inthe steering plate, and a link tiltably installed in the insertiongroove of the steering plate such that the link is configured to rotatein relation to the steering plate around a central axis of the link atleast partially within the insertion groove. An interval between anouter side surface of the link and a side surface of the insertiongroove may be between about 1 mm and about 3 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinventive concepts will be more clearly understood from the followingdetailed description, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view illustrating a steering device for anoverhead hoist transport (OHT) according to some example embodiments;

FIG. 2 is an exploded perspective view illustrating a steering devicefor an OHT according to some example embodiments;

FIG. 3 is an enlarged view illustrating a portion A of FIG. 1;

FIG. 4 is a perspective view illustrating a steering device for an OHTaccording to some example embodiments;

FIG. 5 is an exploded perspective view illustrating a steering devicefor an OHT according to some example embodiments;

FIG. 6 is a graph illustrating impact force on a steering device and/orOHT when the steering device for the OHT is entering a curved portion ofa guide rail (v=1,500 mm/s) according to some example embodiments;

FIG. 7 is a graph illustrating impact force on a steering device and/orOHT when the steering device for the OHT is entering a curved portion ofa guide rail (v=1,500 mm/s) according to some example embodiments;

FIG. 8 is a graph illustrating an amount of vibrations of a steeringdevice and/or OHT at the time of the steering device for the OHTentering the curved portion of a guide rail (v=1,500 mm/s) according tosome example embodiments;

FIG. 9 is a graph illustrating an amount of vibrations of a steeringdevice and/or OHT at the time of the steering device for the OHTentering the curved portion of a guide rail (v=1,500 mm/s) according tosome example embodiments;

FIG. 10 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail N-branch (v=1,000 mm/s) according tosome example embodiments;

FIG. 11 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail N-branch (v=1,000 mm/s) according tosome example embodiments;

FIG. 12 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail branch in a straight line (v=3,300mm/s) according to some example embodiments;

FIG. 13 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail branch in a straight line (v=3,300mm/s) according to some example embodiments;

FIG. 14 is a graph illustrating an amount of vibrations of a steeringdevice and/or OHT coupled to the steering device at the time of thesteering device for the OHT entering a guide rail branch in a straightline (v=3,300 mm/s) according to some example embodiments;

and

FIG. 15 is a graph illustrating an amount of vibrations of a steeringdevice and/or OHT coupled to the steering device at the time of thesteering device for the OHT entering a guide rail branch in a straightline (v=3,300 mm/s) according to some example embodiments.

DETAILED DESCRIPTION

Hereinafter, some example embodiments of the present inventive conceptswill be described with reference to the accompanying drawings.

It will be understood that when an element such as a layer, film,region, or substrate is referred to as being “on” another element, itmay be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present. It willfurther be understood that when an element is referred to as being “on”another element, it may be above or beneath or adjacent (e.g.,horizontally adjacent) to the other element.

It will be understood that elements and/or properties thereof (e.g.,structures, surfaces, directions, or the like), which may be referred toas being “perpendicular,” “parallel,” “coplanar,” or the like withregard to other elements and/or properties thereof (e.g., structures,surfaces, directions, or the like) may be “perpendicular,” “parallel,”“coplanar,” or the like or may be “substantially perpendicular,”“substantially parallel,” “substantially coplanar,” respectively, withregard to the other elements and/or properties thereof.

Elements and/or properties thereof (e.g., structures, surfaces,directions, or the like) that are “substantially perpendicular” withregard to other elements and/or properties thereof will be understood tobe “perpendicular” with regard to the other elements and/or propertiesthereof within manufacturing tolerances and/or material tolerancesand/or have a deviation in magnitude and/or angle from “perpendicular,”or the like with regard to the other elements and/or properties thereofthat is equal to or less than 10% (e.g., a. tolerance of ±10%).

Elements and/or properties thereof (e.g., structures, surfaces,directions, or the like) that are “substantially parallel” with regardto other elements and/or properties thereof will be understood to be“parallel” with regard to the other elements and/or properties thereofwithin manufacturing tolerances and/or material tolerances and/or have adeviation in magnitude and/or angle from “parallel,” or the like withregard to the other elements and/or properties thereof that is equal toor less than 10% (e.g., a. tolerance of ±10%).

Elements and/or properties thereof (e.g., structures, surfaces,directions, or the like) that are “substantially coplanar” with regardto other elements and/or properties thereof will be understood to be“coplanar” with regard to the other elements and/or properties thereofwithin manufacturing tolerances and/or material tolerances and/or have adeviation in magnitude and/or angle from “coplanar,” or the like withregard to the other elements and/or properties thereof that is equal toor less than 10% (e.g., a. tolerance of ±10%)).

It will be understood that elements and/or properties thereof may berecited herein as being “the same” or “equal” as other elements, and itwill be further understood that elements and/or properties thereofrecited herein as being “identical” to, “the same” as, or “equal” toother elements may be “identical” to, “the same” as, or “equal” to or“substantially identical” to, “substantially the same” as or“substantially equal” to the other elements and/or properties thereof.Elements and/or properties thereof that are “substantially identical”to, “substantially the same” as or “substantially equal” to otherelements and/or properties thereof will be understood to includeelements and/or properties thereof that are identical to, the same as,or equal to the other elements and/or properties thereof withinmanufacturing tolerances and/or material tolerances. Elements and/orproperties thereof that are identical or substantially identical toand/or the same or substantially the same as other elements and/orproperties thereof may be structurally the same or substantially thesame, functionally the same or substantially the same, and/orcompositionally the same or substantially the same.

It will be understood that elements and/or properties thereof describedherein as being “substantially” the same and/or identical encompasseselements and/or properties thereof that have a relative difference inmagnitude that is equal to or less than 10%. Further, regardless ofwhether elements and/or properties thereof are modified as“substantially,” it will be understood that these elements and/orproperties thereof should be construed as including a manufacturing oroperational tolerance (e.g., ±10%) around the stated elements and/orproperties thereof.

When the terms “about” or “substantially” are used in this specificationin connection with a numerical value, it is intended that the associatednumerical value include a tolerance of ±10% around the stated numericalvalue. When ranges are specified, the range includes all valuestherebetween such as increments of 0.1%.

FIG. 1 is a perspective view illustrating a steering device for an OHTaccording to some example embodiments, FIG. 2 is an exploded perspectiveview illustrating a steering device for an OHT according to some exampleembodiments, and FIG. 3 is an enlarged view illustrating part A of FIG.1.

Referring to FIGS. 1 to 3, a steering device 100 for OHT according tosome example embodiments, as an example, may include an LM (“LinearMotion”) block 110, a steering plate 120, a link 130, a main bearing140, and a guide roller 150.

The LM block 110 is configured to be movably installed on a guide rail(not shown) on an upper portion of the OHT steering device 100 forsteering of the OHT steering device 100 and is configured to move alongan LM guide rail (not shown). To this end, the LM block 110 may beprovided with an installation groove 112 into which the LM guide rail(not shown) is inserted.

The steering plate 120 is installed on (e.g., fixedly installed to) theLM block 110 to be disposed above the LM block 110. As an example, thesteering plate 120 may have a substantially plate shape. Meanwhile, aninsertion groove 122 into which a lower end portion of the main bearing140 and the link 130 is inserted may be provided on an upper surface 120u of the steering plate 120. Restated, the steering plate 120 mayinclude one or more inner surfaces 120 s and 120 b that collectively atleast partially define an insertion groove 122 into the upper surface120 u the steering plate 120. Restated, the steering plate 120 mayinclude an insertion groove 122. As an example, the insertion groove 122may have a shape corresponding to the shape of the link 130. Inaddition, the steering plate 120 may be provided with an installationprotrusion 124 disposed in the insertion groove 122 and on which themain bearing 140 is installed. As an example, the installationprotrusion 124 may be disposed in a central portion of the insertiongroove 122.

The link 130 is tiltably installed on the steering plate 120 (e.g., istiltably installed in the insertion groove 122 of the steering plate120). As an example, the link 130 may include a plate-shaped body 132insertedly disposed into the insertion groove 122 (e.g., located atleast partially within the insertion groove 122 as shown in at leastFIGS. 1 and 3) and protrusions 134 protruding from both (e.g., opposite)end portions 132 e of an upper surface 132 u of the body 132. Restated,the link 130 may include protrusions 134 protruding from separate,respective (e.g., opposite) end portions 132 e of the upper surface 132u of the body 132. Meanwhile, a through-hole 132 a into which the mainbearing 140 is inserted may be provided in a central portion of the body132. Restated, the body 132 may include one or more inner surfaces 132 idefining the through-hole 132 a in the central portion 132c of the body132 and which extends through the plate-shaped body 132 and which isconfigured to receive the main bearing 140, and/or where the mainbearing 140 is configured to be inserted into the through-hole 132 a, sothat the main bearing is in contact with the link 130 (e.g., the outercircumferential surface 140 s of the main bearing 140 is in flushcontact with the one or more inner surfaces 132 i). As shown, thecentral axis of the through hole 132 a may be coaxial with the centralaxis 139 of the link 130. In addition, the body 132 of the link 130 hasa shape corresponding to the shape of the insertion groove 122, and mayhave a size, smaller than a size of the insertion groove 122. As anexample, as shown in FIG. 3, an interval S (e.g., gap) between an outerside surface 130 s of the link 130, that is, an outer surface 132 s ofthe body 132 and an inner side surface 122 s of the insertion groove 122(e.g., defined by an inner side surface 120 s of the steering plate 120)may be 1 to 3 mm. Accordingly, when an impact is applied to the guideroller 150, the link 130 may be tilted around an installation protrusion124 in the insertion groove 122 within the interval S (e.g., the tiltingmay include rotation 138 around the central axis 139 of the link 130within the insertion groove 122 (where the central axis 139 may becoaxial with a central axis of the main bearing 140 and installationprotrusion 124 and/or may extend perpendicular to the upper surface 120u of the steering plate 120 and/or may extend perpendicular to the uppersurface 132 u of the plate-shaped body 132) within the insertion groove122, where the tilting may include the rotation 138 of the link 130 tomove in an arc within the clearance provided by the interval S betweenpositions at which the outer surface 132 s of the body 132 may contactdifferent parts of one or more inner side surfaces 120 s of the steeringplate 120 that define one or more inner side surfaces 122 s of theinsertion groove 122). Accordingly, it will be understood that the link130 being tiltably installed in the insertion groove 122 refers to thelink 130, being at least partially within the insertion groove 122,being configured to be tilted so as to rotate 138 in an arc in relationto the steering plate 120 around the central axis 139, for example torotate 138 in response to an external force being applied to the link130 (e.g., via protrusions 134).

As an example, the link 130 may include multiple protrusions 134 (e.g.,two protrusions 134) that protrude from opposite end portions 132 e ofthe upper surface 132 u of the body 132. However, the present inventiveconcepts are not limited thereto, and the number of guide rollers 150may be changed.

Meanwhile, when an interval S between the outer surface of the body 132and the inner surface of the insertion groove 122 exceeds about 3 mm, ina curved portion of the guide rail (not shown), an overhead hoisttransport (OHT) may come off and fall. Accordingly, the interval Sbetween the outer surface of the body 132 and the inner surface of theinsertion groove 122 should be about 3 mm or less.

Furthermore, when the interval S between the outer surface of the body132 and the inner surface of the insertion groove 122 is less than about1 mm, the impact transmitted to the guide roller 150 may not bedispersed. Accordingly, the interval S between the outer surface of thebody 132 (e.g., outer surface 132 s) and the inner surface of theinsertion groove 122 (e.g., inner side surface 122 s) should be about 1mm or more.

Accordingly, the interval S between the outer surface of the body 132(e.g., outer surface 132 s) and the inner surface of the insertiongroove 122 (e.g., inner side surface 122 s) should be between about 1 mmand about 3 mm.

The interval S as described herein (and the magnitude thereof) may referto a spacing between the outer side surfaces 130 s of the link 130 andthe inner side surfaces 122 s /120 s when the link 130 is not tilted inrelation to the steering plate 120 such that the spacings S1 and S2 ofopposite outer side surfaces 130 s of the link 130 from respectiveopposing inner side surfaces 122 s of the insertion groove 122 are equalor substantially equal (e.g., the interval S refers to the magnitude ofspacings S1 and/or S2 when the magnitude of spacing S1 equals orsubstantially equals the magnitude of spacing S2).

The main bearing 140 is in contact with the link 130. As shown in atleast FIGS. 1-2, the main bearing may be located between the steeringplate 120 and the link 130. The main bearing 140 may couple the link 130to the steering plate 120. The main bearing 140 may be configured to(e.g., serve to) reduce friction when the link 130 is tilted in relationto the steering plate 120 (e.g., the link 130 is rotated 138 around thecentral axis 139 in relation to the steering plate 120). As an example,the main bearing 140 may have a circular annular shape. As shown, themain bearing 140 may have an outer circumferential surface 140 s thatmay be in contact with the link 130 (e.g., in flush contact with theinner surface 132 i of the link body 132 as shown in at least FIG. 1).Meanwhile, the main bearing 140 is coupled to an installation protrusion124 of the steering plate 120 and is disposed in a through-hole 132 a ofthe link 130. Accordingly, as shown in at least FIG. 2, the steeringplate 120 may include an installation protrusion 124 that is located inthe insertion groove 122 (e.g., protrudes from bottom surface 120 b intothe insertion groove 122) and on which the main bearing 140 isinstalled. For example, the installation protrusion 124 may extend orprotrude into a central opening 140o defined by an inner surface 140 iof the main bearing 140 so that an outer circumferential surface 124s ofthe installation protrusion 124 contacts (e.g., is in flush contactwith) the inner surface 140 i of the main bearing 140.

The guide roller 150 is rotatably installed on the link 130 (e.g., on aprotrusion 134 protruding from the link 130). As an example, the guideroller 150 may be installed (e.g., rotatably installed) on (e.g.,coupled to) a protrusion 134 of the link 130 (where the protrusion 134may be referred to herein as a protrusion protruding from the link 130)via (e.g., through a bearing 102 such that the guide roller 150 isrotatably installed on the protrusion 134. Accordingly, the guide roller150 may be tilted in conjunction with the link 130 (e.g., the tiltingmay include rotation 158 around the central axis 159 of the guide roller150 (where the central axis 159 may be coaxial with a central axis ofthe bearing 102 and protrusion 134). That is, when external force acts,external force applied to the guide roller 150 is transmitted to thelink 130 so that the link 130 is tilted. In this case, a body 132 of thelink 130 may be tilted within the insertion groove 122 to alleviateimpacts caused by external force.

In addition, some example embodiments of the inventive concepts providea steering device for an OHT that can reduce mechanical vibrations andimpacts transmitted to a wafer while the OHT is running.

In some example embodiments, the bearing 102 may be absent and the guideroller 150 may installed on the protrusion 134 to be directly contactingthe protrusion 134.

As an example, the guide roller 150 may be installed on the link 130such that the two thereof form a pair. However, the present inventiveconcepts are not limited thereto, and the number of guide rollers 150may be changed.

As described above, since the link 130 is tiltably installed in theinsertion groove 122 of the steering plate 120 so as to be configured totilt (e.g., rotate 138 in relation to the steering plate 120 aroundcentral axis 139) at least partially within the insertion groove 122(e.g., rotate 138 within the interval S, e.g., about 1 mm to about 3mm), it is possible to reduce or prevent damage to the steering device100 for the OHT based on the steering device 100 including the link 130that is tiltably installed in the steering plate 120. In other words,even when external force is applied to the guide roller 150 due to thecollision between a guide rail (not shown) and the guide roller 150, thelink 130 is tilted (e.g., rotated 138 around central axis 139, forexample rotated 138 within interval S which may be between about 1 mmand about 3 mm) to alleviate impacts. Accordingly, it is possible toreduce or prevent damage to the guide rail and the steering device 100for the OHT based on the steering device 100 including the link 130 thatis tiltably installed in the steering plate 120.

Furthermore, since the link 130 is tiltably installed in the insertiongroove 122 of the steering plate 120, mechanical vibrations and impactstransmitted to the wafer while the OHT is running can be reduced basedon the steering device 100 including the link 130 that is tiltablyinstalled in the steering plate 120.

In some example embodiments, the steering device according to any of theexample embodiments may omit at least some of the elements of thesteering device described according to some example embodiments. Forexample, referring to FIGS. 1-3, in some example embodiments thesteering device 100 may omit at least one of the main bearing 140, oneor more or all of the guide rollers 150, the installation protrusion124, one or more or all of the protrusions 134, or the like. Forexample, in some example embodiments, the steering device 100 mayinclude the LM block 110, the steering plate 120 fixedly installed tothe LM block 110 and including one or more inner surfaces 120 s, 120 bat least partially defining an insertion groove 122 in the steeringplate 120, and a link 130 tiltably installed in the insertion groove ofthe steering plate such that the link is configured to rotate 138 inrelation to the steering plate 120 around a central axis 139 of the link130 at least partially within the insertion groove 122, wherein aninterval S between an outer side surface 130 s of the link 130 (e.g.,outer surface 132 s) and an inner side surface 122 s of the insertiongroove 122 (e.g., inner side surface 120 s) is between about 1 mm andabout 3 mm (e.g., when the link 130 is in a non-tilted state such thatS1 is equal or substantially equal to S2).

FIG. 4 is a perspective view illustrating a steering device for an OHTaccording to some example embodiments, and FIG. 5 is an explodedperspective view illustrating a steering device for an OHT according tosome example embodiments.

Referring to FIGS. 4 and 5, a steering device 200 for an OHT mayinclude, as an example, an LM block 110, a steering plate 220, link 230,a main bearing 240, a guide roller 250, a fixing member 260, and a cover270.

Meanwhile, since the LM block 110 is substantially the same as theabove-described components, a detailed description thereof will beomitted here and will be replaced with the above description.

The steering plate 220 is installed on the LM block 110 so as to bedisposed on the LM block 110. As an example, the steering plate 220 mayhave a substantially plate shape. Meanwhile, an insertion groove 222into which a lower end portion of the link 230 is inserted is formed inthe steering plate 220, and an installation hole 224 in which the fixingmember 260 is installed may be provided in a central portion theinsertion groove 222. As an example, the insertion groove 222 may have ashape corresponding to the shape of the lower end portion of the link230. In addition, the installation hole 224 may have a size throughwhich a fixing member 260 can be installed.

The link 230 is tiltably installed on the steering plate 220 (e.g.,installed on the steering plate 220 and configured to tilt, or rotatearound central axis 299 at least partially within the insertion groove222). As an example, the link 230 may include a plate-shaped body 232insertedly disposed in the insertion groove 222 (e.g., at leastpartially located within the insertion groove 222), and protrusions 234disposed to protrude from both end portions (e.g., opposite end portions232 e) of the upper surface 232 u of the body 232. Restated, the link230 may include protrusions 234 protruding from separate, respective(e.g., opposite) end portions 232 e of the upper surface 232 u of thebody 232. Meanwhile, a through-hole 232 a into which the main bearing240 is inserted may be provided in a central portion of the body 232. Inaddition, the body 232 of the link 230 has a shape corresponding to theshape of the insertion groove 222, and may have a substantiallyrectangular plate shape as an example. Meanwhile, the body 232 of thelink 230 may have a size, smaller than a size of the insertion groove222. As an example, an interval between the outer surface of the body232 and the inner surface of the insertion groove 222 may be about 1 mmto about 3 mm. Accordingly, when an impact (e.g., external force) isapplied to the guide roller 250, the link 230 may be tilted within theinsertion groove 222 in relation to the steering plate 220, for exampletilted within the interval (e.g., about 1 mm to about 3 mm). As anexample, the through-hole 232 a of the link 230 may be formed to bestepped.

The main bearing 240 serves to reduce friction when the link 230 istilted (e.g., rotated around central axis 299). As an example, the mainbearing 240 may have a circular annular shape. Meanwhile, the mainbearing 240 is fixed (e.g., fixed in place so as to not move in the Ydirection) by the fixing member 260 and is disposed in the through-hole232 a of the link 230. For example, the fixing member 260 may beconfigured to fix the main bearing 240 in place (e.g., hold the mainbearing 240 in place in relation to the link 230, the steering plate220, etc.) such that the main bearing is prevented from moving (e.g.,translating) in the Y direction, X direction, and/or Z direction by thefixing member 260 while the main bearing 240 is still configured torotate around a central axis 299. The outer surface 240 s of the mainbearing 240 is disposed to be in contact (e.g., flush contact) with theinner surface 132 i of the link 230. It will be understood that the mainbearing 240 may be located between the steering plate 220 and the link230.

The guide roller 250 is rotatably installed on the link 230. As anexample, the guide roller 250 is installed on the protrusion 234 of thelink 230 via a bearing (not shown). Accordingly, the guide roller 250may be tilted in conjunction with the link 230. That is, when externalforce acts, external force applied to the guide roller 250 istransmitted to the link 230 so that the link 230 is tilted. In thiscase, the body 232 of the link 230 may be tilted within the insertiongroove 222 to alleviate impacts caused by external force.

As an example, the guide roller 250 may be installed on the link 230such that two of thereof form a pair. However, the present inventiveconcepts are not limited thereto, and the number of guide rollers 250may be changed.

The fixing member 260 serves to fix the main bearing 240, and isinsertedly disposed in the through-hole 232 a of the link 230. As anexample, the fixing member 260 may be provided with (e.g., may include)a first fixing member 262 disposed below the main bearing 240 andconfigured to be coupled to a lower portion of the main bearing 240, anda second fixing member 264 coupled to the first fixing member 262 abovethe first fixing member 262 and configured to prevent separation of themain bearing 240 from the link 230. As an example, an inner surface ofthe main bearing 240 is disposed to be in contact with an outer surfaceof a cylindrical portion 262 a of the first fixing member 262, and abottom surface of the main bearing 240 is disposed to be in contact withan upper portion of a disk portion 262 b of the first fixing member 262.Meanwhile, the second fixing member 264 may include a protruding jaw 264a configured to support (e.g., contact and/or apply a force in the Ydirection, X direction, and/or Z direction to) the upper surface 240 uof the main bearing 240.

The cover 270 is disposed (e.g., configured) to cover (e.g., obscureand/or directly contact in the Y direction) an upper portion (e.g.,upper surface 232 u) of the link 230. As an example, the cover 270 mayhave a rectangular plate shape corresponding to the shape of the link230. In addition, the cover 270 may include a first hole 272 throughwhich the second fixing member 264 passes, and a second hole 274 throughwhich the protrusion 234 of the link 230 passes. Meanwhile, the cover270 is disposed (e.g., configured) to cover the main bearing 240together with the link 230. As shown in FIG. 4, the cover 270 may cover(e.g., obscure and/or directly contact in the Y direction) the mainbearing 240 and the insertion groove 222 of the steering plate 220. Asdescribed above, since the cover 270 is installed, it is possible toprevent foreign substances generated when the link 230 is tilted fromleaking externally.

As described above, since the link 230 is installed to be tiltablewithin the insertion groove 222 of the steering plate 220 so as to beconfigured to tilt (e.g., rotate in relation to the steering plate 220around central axis 299) at least partially within the insertion groove222 (e.g., rotate within an interval of about 1 mm to about 3 mm), it ispossible to reduce or prevent damage to the steering device 200 for OHTbased on the steering device 200 including the link 230 that is tiltablyinstalled in the steering plate 220. In other words, even when externalforce is applied to the guide roller 250 due to the collision between aguide rail (not shown) and the steering device 200 for OHT, the link 230may be tilted to alleviate the impact. Accordingly, it is possible toreduce or prevent damage to the guide rail and the steering device 200for the OHT based on the steering device 200 including the link 230 thatis tiltably installed in the steering plate 220.

Furthermore, since the link 230 is attached to be tiltable within theinsertion groove 222 of the steering plate 220, mechanical vibrationsand impacts transmitted to a wafer while the OHT is running can bereduced based on the steering device 200 including the link 230 that istiltably installed in the steering plate 220.

In addition, it is possible to prevent foreign substances generated whenthe link 230 is tilted through the cover 270 from leaking externally.

Hereinafter, with reference to the drawings, an effect of the steeringdevice for an OHT will be described through experimental data of thesteering device for an OHT that includes a tiltably installed link and asteering device that does not include a tiltably installed linkaccording to some example embodiments.

FIG. 6 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device when the steering device for the OHTis entering a curved portion of a guide rail (v=1,500 mm/s) according tosome example embodiments wherein the steering device does not include alink that is tiltably installed on a steering plate of the steeringdevice (e.g., may omit a link entirely or may include a link that isinstalled on a steering plate and is configured to not tilt, or rotatearound a central axis of the link, in relation to the steering plate),FIG. 7 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device when the steering device for the OHTis entering a curved portion of a guide rail (v=1,500 mm/s) according tosome example embodiments wherein the steering device includes a linkthat is tiltably installed on a steering plate of the steering device,FIG. 8 is a graph illustrating an amount of vibrations of a steeringdevice and/or OHT coupled to the steering device at the time of thesteering device for the OHT entering the curved portion of a guide rail(v=1,500 mm/s) according to some example embodiments wherein thesteering device does not include a link that is tiltably installed on asteering plate of the steering device, and FIG. 9 is a graphillustrating an amount of vibrations of a steering device and/or OHTcoupled to the steering device at the time of the steering device forthe OHT entering the curved portion of a guide rail (v=1,500 mm/s)according to some example embodiments wherein the steering deviceincludes a link that is tiltably installed on a steering plate of thesteering device.

As shown in FIGS. 6 and 7, it can be seen that the impact force on asteering device and/or OHT coupled to the steering device when thesteering device for the OHT is entering a curved portion of a guide rail(v=1,500 mm/s) according to some example embodiments wherein thesteering device includes a link that is tiltably installed on a steeringplate of the steering device is reduced by 58% compared to a steeringdevice that does not include a link that is tiltably installed on asteering plate of the steering device. That is, it can be seen that, ina steering device that does not include a link that is tiltablyinstalled on a steering plate of the steering device, when an entryspeed of the steering device to the curved portion of a guide rail is1500 mm/s, the impact force transmitted to the steering device and/orOHT may be 1340 N, but in the steering device for an OHT according tosome example embodiments wherein the steering device includes a linkthat is tiltably installed on a steering plate of the steering device,when the entry speed of the steering device to the curved portion of theguide rails is 1500 mm/s, the impact force transmitted to the steeringdevice and/or OHT may be 553 N.

In addition, as shown in FIGS. 8 and 9, it can be seen that the amountof vibrations of a steering device and/or OHT coupled to the steeringdevice at the time of the steering device for the OHT entering thecurved portion of a guide rail (v=1,500 mm/s)according to some exampleembodiments wherein the steering device includes a link that is tiltablyinstalled on a steering plate of the steering device is reduced by 18%compared to a steering device that does not include a link that istiltably installed on a steering plate of the steering device. That is,it can be seen that, in a steering device that does not include a linkthat is tiltably installed on a steering plate of the steering device,when the entry speed of the steering device to the curved portion of theguide rail is 1500 mm/s, the amount of vibrations transmitted to thesteering device and/or OHT may be 2.04 g, but in the steering device foran OHT according to some example embodiments wherein the steering deviceincludes a link that is tiltably installed on a steering plate of thesteering device, when the entry speed of the steering device to thecurved portion of the guide rail is 1500 mm/s, the amount of vibrationstransmitted to the steering device and/or OHT may be 1.67 g.

As described above, it is possible to reduce the impact forcetransmitted to and the amount of vibrations of the steering deviceand/or OHT when the steering device for the OHT is in the curved portionof the guide rail according to some example embodiments wherein thesteering device includes a link that is tiltably installed on a steeringplate of the steering device.

FIG. 10 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail N-branch (v=1,000 mm/s) according tosome example embodiments wherein the steering device does not include alink that is tiltably installed on a steering plate of the steeringdevice (e.g., may omit a link entirely or may include a link that isinstalled on a steering plate and is configured to not tilt, or rotatearound a central axis of the link, in relation to the steering plate),and FIG. 11 is a graph illustrating impact force on a steering deviceand/or OHT coupled to the steering device at the time of the steeringdevice for the OHT entering a guide rail N-branch (v=1,000 mm/s)according to some example embodiments wherein the steering deviceincludes a link that is tiltably installed on a steering plate of thesteering device.

Here, looking at an N-branch region (e.g., guide rail N-branch), theN-branch region means a region in which a pair of guide rails aredisposed in parallel and a pair of guide rails are connected from oneguide rail to the other guide rail, that is, a region branched from oneguide rail to the remaining guide rails. An N-branch region entry speedmeans a speed at which the steering device enters the branched guiderail in a region in which the guide rail is branched.

As shown in FIGS. 10 and 11, it can be seen that the impact forcetransmitted to the steering device and/or OHT coupled to the steeringdevice at the time of the steering device for the OHT entering a guiderail N-branch (e.g., N-branch region) (v=1,000 mm/s) according to someexample embodiments wherein the steering device includes a link that istiltably installed on a steering plate of the steering device is reducedby 23% compared to a steering device that does not include a link thatis tiltably installed on a steering plate of the steering device. Thatis, in a steering device that does not include a link that is tiltablyinstalled on a steering plate of the steering device, when the N-branchregion entry speed is 1000 mm/s, the impact force transmitted to thesteering device and/or OHT may be 3902 N, but in the steering device foran OHT according to some example embodiments wherein the steering deviceincludes a link that is tiltably installed on a steering plate of thesteering device, when the N-branch entry speed is 1000 mm/s, it can beseen that the impact force transmitted to the steering device and/or OHTmay be 693 N.

As described above, it is possible to reduce the impact forcetransmitted to the steering device and/or OHT in the N-branch region ofthe guide rail by the steering device for an OHT according to someexample embodiments wherein the steering device includes a link that istiltably installed on a steering plate of the steering device.

FIG. 12 is a graph illustrating impact force on a steering device and/orOHT coupled to the steering device at the time of the steering devicefor the OHT entering a guide rail branch in a straight line (v=3,300mm/s) according to some example embodiments wherein the steering devicedoes not include a link that is tiltably installed on a steering plateof the steering device (e.g., may omit a link entirely or may include alink that is installed on a steering plate and is configured to nottilt, or rotate around a central axis of the link, in relation to thesteering plate), FIG. 13 is a graph illustrating impact force on asteering device and/or OHT coupled to the steering device at the time ofthe steering device for the OHT entering a guide rail branch in astraight line (v=3,300 mm/s) according to some example embodimentswherein the steering device includes a link that is tiltably installedon a steering plate of the steering device, FIG. 14 is a graphillustrating an amount of vibrations of a steering device and/or OHTcoupled to the steering device at the time of the steering device forthe OHT entering a guide rail branch in a straight line (v=3,300 mm/s)according to some example embodiments wherein the steering device doesnot include a link that is tiltably installed on a steering plate of thesteering device, and FIG. 15 is a graph illustrating an amount ofvibrations of a steering device and/or OHT coupled to the steeringdevice at the time of the steering device for the OHT entering a guiderail branch in a straight line (v=3,300 mm/s) according to some exampleembodiments wherein the steering device includes a link that is tiltablyinstalled on a steering plate of the steering device.

Here, looking at a speed of a steering device entering a guide railbranch in a straight line, the branch region (e.g., guide rail branch)may be divided into two or more guide rails by branching the guide railfrom one guide rail. An entry speed of the steering device when drivingin a straight line along the existing guide rail rather than drivingwith the branching guide rail in this region is referred to as a speedof entering a branch in a straight line.

As shown in FIGS. 12 and 13, it can be seen that the impact force on asteering device and/or OHT coupled to the steering device at the time ofthe steering device for the OHT entering a guide rail branch in astraight line (v=3,300 mm/s) according to some example embodimentswherein the steering device includes a link that is tiltably installedon a steering plate of the steering device is reduced by 40% compared toa steering device that does not include a link that is tiltablyinstalled on a steering plate of the steering device. That is, it can beseen that, in a steering device that does not include a link that istiltably installed on a steering plate of the steering device, when aspeed of entering a branch in a straight line is 3300 mm/s, the impactforce transmitted to the steering device and/or OHT may be 1090 N, butin the steering device for an OHT according to some example embodimentswherein the steering device includes a link that is tiltably installedon a steering plate of the steering device, when the speed of entering abranch in a straight line is 3300 mm/s, the impact force transmitted tothe steering device and/or OHT may be 648 N.

In addition, as shown in FIGS. 14 and 15, it can be seen that an amountof vibrations of a steering device and/or OHT coupled to the steeringdevice at the time of the steering device for the OHT entering a guiderail branch in a straight line (v=3,300 mm/s) according to some exampleembodiments wherein the steering device includes a link that is tiltablyinstalled on a steering plate of the steering device is reduced by 4.4%compared to a steering device that does not include a link that istiltably installed on a steering plate of the steering device. That is,it can be seen that, in a steering device that does not include a linkthat is tiltably installed on a steering plate of the steering device,when the speed of entering a branch in a straight line is 3300 mm/s, theamount of vibrations transmitted to the steering device and/or OHT maybe 1.14 g, but in the steering device for an OHT according to someexample embodiments wherein the steering device includes a link that istiltably installed on a steering plate of the steering device, when thespeed of entering a branch in a straight line is 3300 mm/s, the amountof vibrations transmitted to the steering device and/or OHT may be 1.09g.

As described above, it is possible to reduce the impact force and theamount of vibrations of to the steering device and/or OHT when drivingin a straight line in the branch region of the guide rail according tosome example embodiments wherein the steering device includes a linkthat is tiltably installed on a steering plate of the steering device.

As set forth above, according to the present inventive concepts, asteering device for an OHT configured to reduce or prevent damage to theguide rail and the steering device for an OHT may be provided.

In addition, a steering device for an OHT capable of reducing mechanicalvibrations and impact transmitted to a wafer while the OHT is runningmay be provided.

The various and advantageous advantages and effects of the presentinventive concepts are not limited to the above description, and can bemore easily understood in the course of describing some exampleembodiments of the present inventive concepts.

While some example embodiments have been illustrated and describedabove, it will be apparent to those skilled in the art thatmodifications and variations could be made without departing from thescope of the present inventive concepts as defined by the appendedclaims.

What is claimed is:
 1. A steering device for an OHT, the steering devicecomprising: a linear motion (LM) block; a steering plate fixedlyinstalled to the LM block, the steering plate including one or moreinner surfaces at least partially defining an insertion groove in thesteering plate; a link tiltably installed in the insertion groove of thesteering plate; a main bearing having an outer circumferential surfacein contact with the link, the main bearing configured to reduce frictionwhen the link is tilted in relation to the steering plate; and a guideroller rotatably installed on a protrusion protruding from the link. 2.The steering device of claim 1, wherein an interval between an outerside surface of the link and a side surface of the insertion groove isbetween about 1 mm and about 3 mm.
 3. The steering device of claim 1,wherein the steering plate includes an installation protrusion that isin the insertion groove and on which the main bearing is installed. 4.The steering device of claim 1, wherein the link includes a plate-shapedbody at least partially located within the insertion groove, theprotrusion is protruding from an end portion of an upper surface of theplate-shaped body, and the plate-shaped body includes one or more innersurfaces defining a through-hole extending through the plate-shaped bodyin a central portion of the plate-shaped body, wherein the main bearingis configured to be inserted into the through-hole to be in contact withthe link.
 5. The steering device of claim 4, wherein the guide roller isrotatably installed on the protrusion through a bearing.
 6. The steeringdevice of claim 1, further comprising: a cover configured to cover anupper portion of the link.
 7. The steering device of claim 1, furthercomprising a fixing member configured to fix the main bearing in place.8. The steering device of claim 7, wherein the fixing member includes afirst fixing member coupled to a lower portion of the main bearing, anda second fixing member coupled to the first fixing member and configuredto prevent separation of the main bearing from the link.
 9. The steeringdevice of claim 8, wherein the second fixing member includes aprotruding jaw configured to support an upper surface of the mainbearing.
 10. A steering device for an OHT, the steering devicecomprising: a linear motion (LM) block; a steering plate fixedlyinstalled on an upper surface of the LM block, the steering plateincluding one or more inner surfaces at least partially defining aninsertion groove in an upper surface of the steering plate; a link thatis at least partially within the insertion groove and is configured tobe tilted in response to an external force being applied to the link; amain bearing between the steering plate and the link; a guide rollerrotatably installed on an installation protrusion protruding from thelink; a cover configured to cover the main bearing and the insertiongroove of the steering plate; and a fixing member extending through thesteering plate, the fixing member configured to fix the main bearing inplace.
 11. The steering device of claim 10, wherein an interval betweenan outer side surface of the link and a side surface of the insertiongroove between about 1 mm and about 3 mm.
 12. A steering device for anOHT, the steering device comprising: a linear motion (LM) block; asteering plate fixedly installed to the LM block, the steering plateincluding one or more inner surfaces at least partially defining aninsertion groove in the steering plate; and a link tiltably installed inthe insertion groove of the steering plate such that the link isconfigured to rotate in relation to the steering plate around a centralaxis of the link at least partially within the insertion groove, whereinan interval between an outer side surface of the link and a side surfaceof the insertion groove is between about 1 mm and about 3 mm.
 13. Thesteering device of claim 12, further comprising: a main bearing havingan outer circumferential surface in contact with the link, the mainbearing configured to reduce friction when the link is tilted inrelation to the steering plate; and a guide roller rotatably installedon a protrusion protruding from the link.
 14. The steering device ofclaim 13, wherein the steering plate includes an installation protrusionthat is in the insertion groove and on which the main bearing isinstalled.
 15. The steering device of claim 13, wherein the linkincludes a plate-shaped body at least partially located within theinsertion groove, the protrusion is protruding from an end portion of anupper surface of the plate-shaped body, and the plate-shaped bodyincludes one or more inner surfaces defining a through-hole extendingthrough the plate-shaped body in a central portion of the plate-shapedbody, wherein the main bearing is configured to be inserted into thethrough-hole to be in contact with the link.
 16. The steering device ofclaim 13, wherein the guide roller is rotatably installed on theprotrusion through a bearing.
 17. The steering device of claim 1,further comprising: a cover configured to cover an upper portion of thelink.
 18. The steering device of claim 13, further comprising a fixingmember configured to fix the main bearing in place.
 19. The steeringdevice of claim 18, wherein the fixing member includes a first fixingmember coupled to a lower portion of the main bearing, and a secondfixing member coupled to the first fixing member and configured toprevent separation of the main bearing from the link.
 20. The steeringdevice of claim 19, wherein the second fixing member includes aprotruding jaw configured to support an upper surface of the mainbearing.